Systematic optimization of 1 Gbit perpendicular magnetic tunnel junction arrays for 28 nm embedded STT-MRAM and beyond

Park, C.; Kan, Jimmy J.; Ching, Chi; Ahn, Jaehwan; Xue, Lin; Wang, R.; Kontos, A.; Liang, Shuai; Bangar, Mangesh A.; Chen, H.; Hassan, Sajjad; Gottwald, Matthias; Pakala, Mahendra; Kang, Sungwon

doi:10.1109/iedm.2015.7409771

Cited by 33 publications

(10 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…C1 and D1). Besides the reduced fluctuation time scales, SAF free layers have the advantage that the fixed layer in the MTJ can be a perpendicular anisotropy magnet (PMA) which is commonly used in MTJ technology [39,40]. The Langevin equation for the angular coordinate for EPM is…”

Section: Discussionmentioning

confidence: 99%

Subnanosecond Fluctuations in Low-Barrier Nanomagnets

et al. 2019

View full text Add to dashboard Cite

Fast magnetic fluctuations due to thermal torques have useful technological functionality ranging from cryptography to probabilistic computing. The characteristic time of fluctuations in typical uniaxial anisotropy magnets studied so far is bounded from below by the well-known energy relaxation mechanism. This time scales as α −1 , where α parameterizes the strength of dissipative processes. Here, we theoretically analyze the fluctuating dynamics in easy-plane and antiferromagnetically coupled nanomagnets. We find in such magnets, the dynamics are strongly influenced by fluctuating intrinsic fields, which give rise to an additional dephasing-type mechanism for washing out correlations. In particular, we establish two time scales for characterizing fluctuations (i) the average time for a nanomagnet to reverse-which for the experimentally relevant regime of low damping is governed primarily by dephasing and becomes independent of α, (ii) the time scale for memory loss of a single nanomagnet-which scales as α −1/3 and is governed by a combination of energy dissipation and dephasing mechanism. For typical experimentally accessible values of intrinsic fields, the resultant thermal-fluctuation rate is increased by multiple orders of magnitude when compared with the bound set solely by the energy relaxation mechanism in uniaxial magnets. This could lead to higher operating speeds of emerging devices exploiting magnetic fluctuations.

show abstract

Section: Discussionmentioning

confidence: 99%

Subnanosecond Fluctuations in Low-Barrier Nanomagnets

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Such magnets with diameters that are less than about 100 nm have been shown to exhibit monodomain behavior [19]- [21]. It is important to note that while modifying existing interfacial PMA free layers by modulating the thickness to make them IMA seems relatively straightforward, replacing highly optimized fixed PMA layers [22] with IMA stacks could prove more challenging. The time scale of fluctuations can be very different for the two categories of low barrier magnets as shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Low-Barrier Magnet Design for Efficient Hardware Binary Stochastic Neurons

et al. 2019

View full text Add to dashboard Cite

Binary stochastic neurons (BSN's) form an integral part of many machine learning algorithms, motivating the development of hardware accelerators for this complex function. It has been recognized that hardware BSN's can be implemented using low barrier magnets (LBM's) by minimally modifying presentday magnetoresistive random access memory (MRAM) devices. A crucial parameter that determines the response of these LBM based BSN designs is the correlation time of magnetization, τc. In this letter, we show that for magnets with low energy barriers (∆ ≈ kBT and below), circular disk magnets with inplane magnetic anisotropy (IMA) lead to τc values that are two orders of magnitude smaller compared to τc for magnets having perpendicular magnetic anisotropy (PMA) and provide analytical descriptions. We show that this striking difference in τc is due to a precession-like fluctuation mechanism that is enabled by the large demagnetization field in IMA magnets. We provide a detailed energy-delay performance evaluation of previously proposed BSN designs based on Spin-Orbit-Torque (SOT) MRAM and Spin-Transfer-Torque (STT) MRAM employing low barrier circular IMA magnets by SPICE simulations. The designs exhibit sub-ns response times leading to energy requirements of ∼a few fJ to evaluate the BSN function, orders of magnitude lower than digital CMOS implementations with a much larger footprint. While modern MRAM technology is based on PMA magnets, results in this paper suggest that low barrier circular IMA magnets may be more suitable for this application.Index Terms-Binary stochastic neuron, hardware implementation, low barrier magnet, embedded MTJ, probabilistic computing

show abstract

“…Rapid development of spintronic devices in the past decades has laid a solid foundation for emerging applications. For instance, in 2015, STT‐MRAM with capacity of 1 Gbit was presented with 40–50 nm perpendicularly magnetized MTJs . Later in 2016, Chung et al demonstrated 4 Gbit STT‐MRAM with cell projection area of 9F 2 .…”

Section: Discussionmentioning

confidence: 99%

Modulation of Heavy Metal/Ferromagnetic Metal Interface for High‐Performance Spintronic Devices

Peng

Zhu

Zhou

et al. 2019

Adv Elect Materials

View full text Add to dashboard Cite

Spintronic devices such as magnetic tunnel junctions and skyrmions have attracted considerable attention due to features such as nonvolatility, high scalability, low power, and high speed. Over the past few years, innovative materials and new structures in this field have resulted in the emergence of new phenomena and exciting device performance. It has been found that the heavy metal (HM)/ferromagnetic metal (FM) interface plays an essential role in spintronic devices. Spintronic device performance can be significantly enhanced through proper modulation of this interface. Recent progress in this blooming field is reviewed with specific emphasis on the HM/FM interface. Investigations into HM/FM-interface-related phenomena, including perpendicular magnetic anisotropy, tunnel magnetoresistance, magnetic damping, spin-orbit torque, and Dzyaloshinskii-Moriya interaction, are put into context. Guidelines for realizing high-performance spintronic devices are provided, and an outlook on their future research direction and potential applications is given.

show abstract

Systematic optimization of 1 Gbit perpendicular magnetic tunnel junction arrays for 28 nm embedded STT-MRAM and beyond

Cited by 33 publications

References 3 publications

Subnanosecond Fluctuations in Low-Barrier Nanomagnets

Subnanosecond Fluctuations in Low-Barrier Nanomagnets

Low-Barrier Magnet Design for Efficient Hardware Binary Stochastic Neurons

Modulation of Heavy Metal/Ferromagnetic Metal Interface for High‐Performance Spintronic Devices

Contact Info

Product

Resources

About